Printing apparatus

ABSTRACT

Adjacent pattern-shaped electrographic electrodes are in motion in a plane parallel to the recording medium during the time they apply a charge to the medium. With the motion in a suitable pattern, such as an orbital pattern, the charge pattern laid down by an electrode may be spaced from that of an adjacent electrode less than the distance between these electrodes. Operating in this way makes it possible to have two adjacent electrodes spaced a sufficient distance from one another to avoid voltage breakdown between these electrodes, when one electrode is on and the other off, but still permits the respective charged patterns produced by these electrodes, when they are both on, to be closer than this distance to one another or even to overlap.

United States Patent 1191 Hatsell Jan. 22, 1974 PRINTING APPARATUS Prima ExaminerL. T. Hix 7 1 tzWll Ald HtsellWld, 5] men or g g en a ay an Attorney, Agent, or Fzrm--Harold Christoffersen [73] Assrgnee: RCA Corporatlon, New York, NY. ABSTRACT [22] Ffled: 1972 Adjacent pattern-shaped electrographic electrodes are [21] Appl. No.: 307,016 in motion in a plane parallel to the recording medium during the time they apply a charge to themedium. i Apphcatmn Data With the motion in a suitable pattern, such as an or- [63] Cgmtmuaton of Ser. No. 204,891, Dec. 6, 1971, bital pattern, the charge pattern laid down by an elec a andme trode may be spaced from that of an adjacent electrode less than the distance. between these electrodes. g? g g g g bg g 2 Operating in this way makes it possible to have two j i 3 g 4 6 A 1 /0 adjacent electrodes spaced a sufficient distance from 1 o arc l 2 2 533 one another to avoid voltage breakdown between H4 5 these electrodes, when one electrode is on and the other off, but still permits the respective charged pat- [56] References Clted terns produced by these electrodes, when they are UNITED STATES PATENTS both on, to be closer than this distance to one another 3,449,753 6/1969 Starr, Jr. 346/74 ES or even to overlap. 3,528,073 9/1970 Starr, Jr. 346/74 ES 3,611,419 10/1971 Blumenthal 346/74 ES 3 Clams, 5 Drawmg Flgul'es POWER SUPPLY 200 TO CONDUTIVE ELASTOMER HO PATENTEU JAN 2 21374 SHEET 1 0F 3 sum 3 or 3 \d (-30ov) 210 v Er O V) I20 224 20 0 POWER SUPPLY 200 A TO CONDUTIVE ELASTOMER no PRINTING APPARATUS This is a continuation, of application Ser. No. 204,891, filed Dec. 6, 1971 now abandoned.

BACKGROUND OF THE INVENTION In some forms of electrographic printing apparatus a charge pattern is applied to a recording medium from one or more symbol-shaped electrodes in contact with the recording medium by applying a relatively large voltage betweeen selected ones of the electrodes, on the one hand, and a reference electrode beneath the recording medium, one the other hand. The electrodes not selected are at some other potential from that of the selected ones such as the potential of the reference electrode. Accordingly, a relatively large difference in potential exists between a selected and a nonselected, symbol-shaped electrode. This means that no two such electrodes can be spaced closer to one another than some minimum distance at which voltage breakdown will occur. On the other hand, it may be desirable to be able to produce charge patterns corresponding to two adjacent selected electrodes which are closer to one another than this minimum distance of even which overlap. This problem is dealt with and solved in the present application.

SUMMARY OF THE INVENTION Apparatus for applying a chargepattern to a recording medium includes a symbol electrode means in contact with one surface of the recording medium a reference electrode means also in contact with the recording medium and a means for applying a voltage between the two.

During the time that voltage is being applied, relative motion is created between the symbol electrode means and recording medium for increasing the size of the charge pattern.

BRIEF DESCRIPTION OF THE DRAWING DETAILED DESCRIPTION In FIG. 1 where the invention is employed in an electrographic label printing apparatus, a strip of recording medium extends from a roll of paper 12 mounted on a spindle l4. Spindle 14 is attached to a frame 16 to Recording medium 10 next passes over a buffer arm assembly 20. The buffer arm assembly 20 comprises a freely rotatable roller 22, over which the recording medium passes, attached to one end of an arm 24. The other end of the arm is pivotable about an axle 26 which is secured to the frame 16. A spring 28 couples between arm 24 and the frame.

The recording medium 10 next passes over a drag brake roller 30 and through a series of stations which together produce a visible image on the recording medium and prepare the medium for application to a container. These stations are a charge application station 34, a toning and fixing station 36, an adhesive application station 38 and a cutting and ejection station 44. Charge application station 34, which will be described in greater detail in connection with FIGS. 2-5, applies a charge pattern to the underside (as illustrated) of recording medium 10 while it is stationary. After the charge pattern is applied, clutch and brake assembly is engaged causing rollers 40 and 42 to drive the portion of the recording medium 10 to which the charge pattern has been applied into toner and fixer station 36. A pump 50 at this station is located in a container 52 of toner 54. As recording medium 10 passes through the fixer station, pump 50 forces a stream of the toner such as one containing graphite particles onto the portion of the recording medium containing the charge pattern previously applied at station 34. A toning ground plane 60 on the backside of recording medium 10 helps to ensure the the positively charged graphite particles in the toner are attracted to the negative charge pattern on recording medium 10.

The recording medium 10 is next driven by rollers 40 and 42 between a pair of rollers 64 and 66 located in toning station 36. The purpose of these rollers is to remove excess toner from the recording medium. A scraper 68 serves to remove any graphite toning particles from roller 66 as it is rotated by the recording medium. Also located in toning station 36 is a fixing lamp 70 surrounded by a reflector 72. This combination directs heat toward the recording medium causing evaporation of the toner carrier.

Next rollers 40 and 42 rotate to propel the portion of the recording medium 10 now having a visible image thereon, into the adhesive application station 38. An adhesive strip extends from a roll of adhesive 82 which is mounted on a spindle 84. Spindle 84, mounted on the backplate 16, includes a drag brake to prevent excessive payout of the adhesive strip. The adhesive strip passes over a buffer arm assembly over a roller 92 and then between rollers 94 and 96. Rollers 94 and 96 are freely rotatable on axes secured to the frame 16 and are positioned to press the adhesive strip against the back surface of recording medium 10 (i.e., the surface opposite that on which the image appears).

After the recording medium passes between drive rollers 40 and 42, it enters the cutting and dispensing station 44. At this point individual labels may be cut by cutting bars 97 and 98, one of the two being fixed and the other being movable either by a solenoid assembly (not shown) or any other conventional driving arrangement. Alternatively, if a strip of labels rather than individual labels is desired, the cutting bars are not activated. In any event, the label then passes out through a dispenser 99 which holds the label until it is removed either manually or by automatic apparatus, not shown.

Summarizing the operation of the FIG. 1 system, the desired charge pattern is applied to recording medium at the charge application station 34 while the recording medium is stationary. As mentioned previously, the operation of this station will be described in detail in connection with FIGS. 2-5. After the charge has been applied, clutch and brake assembly 46 may be engaged to causethe motor 48 to drive rollers 40 and 42. The rollers rapidly propel the portion of the recording medium containing the image into the toner station 36 and past pump 50. The buffer arm assemblies and 90 are positioned to provide-the necessary slack required to permit rapid movement of the recording medium without initial rapid movement of rolls .12 and 82 in view of the relatively high inertia exhibited by these rolls.

As the portion'of the recording medium 10 containing the charge pattern passes pump 50, a stream of toner fluid is propelled against the recording medium adhering to the portions to which a charge has been applied at station 34. Clutch and brake 46 is disengaged while the charged portion of thelabel is between pump 50. and rollers 64, 66 so that the charge pattern for the next label may be applied at charge application station 34. Clutch and brake assembly 46 is then again energized to drive the recording medium containing the image with toner particles applied past fixing lamp 70, where the toner carrier is evaporated off and the toner particles are fixed to the recording medium, to a point between lamp 72 and rollers 94,96. There, clutch and brake 46 is disengaged to permit a charge to be applied at station 34 for yet another label. Clutch and brake assembly 46 is once again engaged to bring the portion of the recording medium containing the now visible image past adhesive application station 38 where adhesive backing is applied to the label. This adhesive backing enables the label to be affixed to whatever container (not shown) the label is describing. Finally, the clutch and. brake assembly once again is engaged to bring the recording medium into cutting station 44. Here, as previously mentioned, it may be cut or alternatively a strip of labels may simply be dispensed from dispenser 99 to be cut at a later point in' time.

In the charge application station of FIG. 2, recording medium 10, shown in phantom, passes between a conductive elastomer 110 and a printed circuit board 112. The printed circuit board, illustrated in FIGS. 3 and 4, comprises a plurality of concentric, circularly shaped electrodes 120 flush-mounted in a suitable dielectric material such as glass-filled epoxy. A plurality of barshaped electrodes 124 (upper left of board in FIG. 3) are similarly imbedded in the glass epoxy material 122 such that their upper surface is flush with the upper surface of the glass epoxy board. As best seen in FIG. 4, which is a cross-section along lines 4--4 of FIG. 3, conductive posts 130 connect the circular electrodes 120 to conductors 132 located on the underside of the board. The conductors 132 may run to the edge of the printed circuit board. Standard printed circuit board edge connectors may couple these conductors to other electrical circuitry, as illustrated schematically in FIG. 3.-

Returning to FIG. 2, printed circuit board 112 is bonded to an insulator 140. The insulator is in turn bonded to a metal plate 142. A ball-bearing assembly 144 is mechanically attached to the plate in a conventional manner. The upper portion 150 of a shaft 152 resides in ball-bearing assembly 144. The center line 154 of shaft portion 150 is offset somewhat from the center line 156 of the remainder of the shaft 152. Shaft 152 resides in upper bearing assembly 158 and lower bearing assembly 160. The bearing assemblies are mechanically connected to a housing 162 which in turn is mechanically connected to backplate 16 by a support assembly 164.

A pulley 166 is attached to the end of shaft 152 opposite the offset portion 150. A suitable driving means 170, such as a motor, attached to backplate 16 is adapted to drive pulley 166 and therefore shaft 152 via a belt 172.

' With the arrangement described, as motor 170 rotates, shaft 152 is caused to rotate. Because of the off set portion 150 of shaft 152, printed circuit board 112 moves in an orbital path about center line 156. As the only link between printed circuit board 112 and shaft 152 is the ball-bearing assembly 144, the printed circuit board would have a tendency to rotate as shaft 152 rotates. Such tendency to rotate is prevented by pin 174 which is attached to an extension 176 of housing 162. The pin resides in an over-sized opening 178 in plate 142.

Assembly 180 is located opposite printed circuit board l12 and above recording medium 10. This assembly forces the recording medium against printed circuit board 112 during the time that charge is being applied to it. The conductive elastomer 110 which is above and in contact with recording medium 10 is sup ported by a stiffening plate 182. Four guide pins 184 (only two of which are visible), reside in four closefitting openings in plate 182 and provide directional guidance to plate 182 permitting it to move only in the vertical direction indicated by arrow 185. Pins 184 are in turn supported by a support bracket 186 a portion of which is broken away so that the other components are visible. Bracket 186 is attached to backplate 16.

Compression springs 188 on each pin 184 normally are operative to keep the conductive elastomer 110 a slight distance away from printed circuit board 112. Cams 190, the shape of which are best seen in FIG. 1, are attached to a shaft 192 to be rotated thereby. The cams cause plate 182, and therefore conductive elastomer 110 to be forced downward a sufficient distance to cause recording medium 10 to come into intimate contact with printed circuit board 1 12. The conductive elastomer 110 in contact with the reverse side of the recording medium acts both as the common electrode needed to provide an electrical path and to eliminate the effect of any printed circuit board uneveness or lack of parallelism between assembly 180 and printed circuit board 112. Shaft 192 is attached to a pulley 194 which is in turn coupled by any suitable means to drive motor 48. A microswitch 196 may be adapted to a close only when the conductive elastomer 110 is away from printed circuit board 112. The miniature switch 196 may be electrically connected to clutch and brake assembly 46 (FIG. 1) so that the clutch and brake are only engaged to move recording medium 10 when it is free to move.

Returning to FIG. 3, there is shown the electrical interconnection between the circular electrodes 120, bar electrodes 124 and a direct voltage power supply 200. Power supply 200 may be of any conventional design capable of producing two voltages one each at terminals V and V The power supply is also connected to conductive elastomer 110 (FIG. 2) which serves as a reference electrode. Voltage V is coupled through a momentary switch means 202 to a first plurality of switches 204-l to 204-7 to a second plurality of switches 206-1 to 206-3 and to circular electrode 224. Each of the switches 204 is connected to an electrode 124 and each of the switches 206 is connected to an electrode 120. Each of the bar electrodes 124 and circular electrodes 120 are coupled to one end of identical resistors 210. The other end of all resistors 210 are coupled to power supply terminal V The switches 204 and 206 enable certain electrodes to be selected while others are not selected. For example, the switches 204 may be thrown to positions such that the electrodes connected to switches 204-1, 2, 3, 7 are selected and the electrodes connected to switches 204-4, 5, 6 are not selected. In this case, when momentary switch 202 is depressed, the first mentioned group of electrodes will be placed at a potential-of 600 volts relative to conductive elastomer 110 (which is at ground) while the second group of electrodes will be at a potential of 300 volts. Since recording medium 10 is of the type which requires a potential difference of over 300 volts before a significant charge pattern is created sufficient to cause toner particles to be attracted, nonselectedelectrodes (those at a potential of 300 volts) will not charge the recording medium sufficiently to attract toner particles. When switch 202 is not depressed all electrodes will be at a potential of 300 volts.

Because of the switching arrangement illustrated in FIG. 3, any one or more of the electrodes .120 or 124 can be placed at a potential of either 3OO volts or -60() volts when switch 202 is closed. For example, with switches 206-1 and 206-2 closed, electrode 220 can be placed at a potential 300 volts while its two adjacent electrodes 222 and 224 and electrode 240 are at --600 volts. The separation between adjacent electrodes is sufficient to prevent voltage breakdown between a selected electrode (i.e., one that has 600 volts on it) and an adjacent nonselected electrode (i.e., one that has -300 volts on it).

Voltage V and the resistors to which it is coupled are not absolutely essential to the proper functioning of the apparatus. However, by having voltage V and therefore having at most a potential difference of only 300 volts between a selected and nonselected electrode, it is possible to have electrodes spaced closer together than would be possible if the voltage switches between 0 volts (i.e., ground) and -600 volts. While switch 202 is shown as a momentary pushbutton switch, it may be automatically activated at a desired time by any conventional means. For example, referring momentarily to FIG. 2, charge application to the recording medium 10 is desired only when the recording medium is forced into intimate contact with printed circuit board 112 by the assembly 180. Therefore, switch 196 may be altered to include switch 202. As a result of the orbital motion created by the mechanism of FIG. 2, the electrodes create a charge pattern on the recording medium much larger than the size of each electrode. For example, the charge pattern from electrode 222 may extend from dotted line 230 to dottled line 232 while the charge pattern from electrode 240 may extend from dashed line 232 to dashed line 244. Thus due to the orbital motion, the pattern created by two adjacent electrodes 222 and 240 actually abut. By means of a larger orbit the patterns may be caused to overlap. F IG. 5 illustrates a label created bythe electrodes of FIG. 3. There the large outer ring 250 is created by electrodes 222 and 240 while the inner bulls-eye 252 is created by electrode 224. Likewise the numeral 7 is created by various ones of electrodes 124 which have 600 volts applied to them.

It is to be understood that although the invention has been described in terms of an electrographic apparatus for producing labels, it is suitable in any application requiring a pattern which must be made larger than the size of the electrodes producing that pattern. Also while the motion of the electrodes to create the desired pattern in this application is an orbital one, any type of motion which creates the desired size of pattern relative to the electrode size is suitable. Thus for example if only a bar code were used such as is used to create the numeral 7, then perhaps a rectangular motion of the electrode relative to the recording medium would be most desirable. Further either the electrodes can be made to move while the recording medium is kept stationary or the recording medium may be moved while the electrodes are kept stationary or both may be moved to create the desired pattern.

Further, while electrographic apparatus for applying a charge pattern has been described, the invention is not limited thereto. Thus, for example, recording medium 10 may be heat sensitive paper. Then selected electrode may be heated to alter the appearance of the paper beneath the selected electrode. Here again if a selected electrode and adjacent nonselected electrode are too close, the non-selected electrode may be heated sufficiently to cause discoloration of the recording medium. The solution as with electrographic apparatus is to separate the electrodes and then move the assembly over the recording medium to derive sufficient closeness between adjacent symbols.

The apparatus just described has been found to work satisfactorily with the following products:

Recording medium 10 Scott-Graphics No. 568

Toner 54 Scott-Graphics No. TlO-SO What is claimed is:

1. Apparatus for applying a charge pattern to a recording medium comprising, in combination:

symbol electrode means comprising at least one symbol-shaped electrode adjacent to one surface of said recording medium;

reference electrode means adjacent to a surface of said recording medium;

means for applying a voltage between said symbol electrode means and said reference electrode means for creating a charge pattern on said recording medium the same shape as said symbol-shaped electrode; and

means for creating relative motion in a plane parallel to said one surface of said recording medium between said recording medium and said electrode means during the application of said voltage for increasing the size of said charge pattern.

2. The combination as set forth in claim 1 wherein said symbol electrode means comprises a plurality of symbol-shaped electrodes, spaced from one another sufficient distances to prevent voltage breakdown between symbol-shaped electrodes which may be at different operating potentials and further including means for applying said voltage between selected ones, which 7 may be less than all, of said symbol-shaped electrodes and said reference electrode means.

3. The combination as set forth in claim 2 wherein said motion creating means creates motion to move said selected ones of said electrodes to create a charge pattern at least a portion of which is opposite a portion ofsaid electrode means occupied by a said nonselected electrode during some portion of movement.

4. The combination as set forth in claim 2 wherein said symbol electrode means comprises a plurality of concentric electrodes and wherein said motion producing means comprises orbital motion creating means.

5. Apparatus for applying a pattern to a recording surface of a record medium, comprising, in combinatron:

symbol means comprising at least one symbol-shaped surface adjacent to said surface of said record medium; means for creating on the part of said record medium adjacent said symbol means by said symbol means a pattern of the same shape as said symbol-shaped means surface; and means for creating in a plane parallel to said recording surface of said record medium relative motion between said record medium and said symbol means surface to increase the size of said pattern relative to the size of said symbol means surface. 6. The apparatus set forth in claim 5, wherein said symbol means surface includes at least two symbolshaped electrodes; and additionally including reference electrode means adjacent a surface of said recording medium which is disposed oppositely to said recording surface; and wherein said means for creating by said symbol means on the part of said record medium adjacent said symbol means a pattern includes an energy applying means which is operative for increasing the voltage differential between a selected one of said symbol-shaped electrodes and said reference electrode means with respect to voltage differential between a non-selected one.of said symbol-shaped electrodes and said reference electrode means; the pattern thereby created on said recording surface being in the form of an electric charge; the said shaped electrodes being spaced from one another by distances sufficient to prevent voltage breakdown between selected and nonselected symbol-shaped electrodes;

and wherein;

said means for creating relative motion decreases to a distance not greater than the spacing between adjacent selected electrodes the spacing between patterns created on said recording surface byjadjacent selected ones of said electrodes.

7. The apparatus set forth in claim 6, wherein said means for creating motion creates motion sufficient to createa charge pattern corresponding to any selected electrode overlapping at least a portion of the charge pattern created by the one of said electrodes next adjacent said any selected electrode.

8. The combination as set forth in claim 6, wherein said shaped electrodes comprise a plurality of circular, concentric electrodes;

and wherein;

said means for creating motion causes such concentric electrodes to move in an orbital path about a point displaced from the center of said circular concentric electrodes. 

1. Apparatus for applying a charge pattern to a recording medium comprising, in combination: symbol electrode means comprising at least one symbol-shaped electrode adjacent to one surface of said recording medium; reference electrode means adjacent to a surface of said recording medium; means for applying a voltage between said symbol electrode means and said reference electrode means for creating a charge pattern on said recording medium the same shape as said symbolshaped electrode; and means for creating relative motion in a plane parallel to said one surface of said recording medium between said recording medium and said electrode means during the application of said voltage for increasing the size of said charge pattern.
 2. The combination as set forth in claim 1 wherein said symbol electrode means comprises a plurality of symbol-shaped electrodes, spaced from one another sufficient distances to prevent voltage breakdown between symbol-shaped electrodes which may be at different operating potentials and further including means for applying said voltage between selected ones, which may be less than all, of said symbol-shaped electrodes and said reference electrode means.
 3. The combination as set forth in claim 2 wherein said motion creating means creates motion to move said selected ones of said electrodes to create a charge pattern at least a portion of which is opposite a portion of said electrode means occupied by a said nonselected electrode during some portion of movement.
 4. The combination as set forth in claim 2 wherein said symbol electrode means comprises a plurality of concentric electrodes and wherein said motion producing means comprises orbital motion creating means.
 5. Apparatus for applying a pattern to a recording surface of a record medium, comprising, in combination: symbol means comprising at least one symbol-shaped surface adjacent to said surface of said record medium; means for creating on the part of said record medium adjacent said symbol means by said symbol means a pattern of the same shape as said symbol-shaped means surface; and means for creating in a plane parallel to said recording surface of said record medium relative motion between said record medium and said symbol means surface to increase the size of said pattern relative to the size of said symbol means surface.
 6. The apparatus set forth in claim 5, wherein said symbol means surface includes at least two symbol-shaped electrodes; and additionally including reference electrode means adjacent a surface of said recording medium which is disposed oppositely to said recording surface; and wherein said means for creating by said symbol means on the part of said record medium adjacent said symbol means a pattern includes an energy applying means which is operative for increasing the voltage differential between a selected one of said symbol-shaped electrodes and said reference electrode means with respect to voltage differential between a non-selected one of said symbol-shaped electrodes and said reference electrode means; the pattern thereby created on said recording surface being in the form of an electric charge; the said shaped electrodes being spaced from one another by distances sufficient to prevent voltage breakdown between selected and non-selected symbol-shaped electrodes; and wherein; said means for creating relative motion decreases to a disTance not greater than the spacing between adjacent selected electrodes the spacing between patterns created on said recording surface by adjacent selected ones of said electrodes.
 7. The apparatus set forth in claim 6, wherein said means for creating motion creates motion sufficient to create a charge pattern corresponding to any selected electrode overlapping at least a portion of the charge pattern created by the one of said electrodes next adjacent said any selected electrode.
 8. The combination as set forth in claim 6, wherein said shaped electrodes comprise a plurality of circular, concentric electrodes; and wherein; said means for creating motion causes such concentric electrodes to move in an orbital path about a point displaced from the center of said circular concentric electrodes. 